The present invention relates generally to grain stirring apparatus as for use in storage bins employing multiples of down augers carried on a horizontal support member which moves in an arcuate path about the center point of a circular bin, and more particularly to those devices which reciprocate the augers radially back and forth along the support member as it moves in order to accomplish more complete coverage of the grain.
The prior art reciprocates the down augers in circular bins as the support member revolves about the center point in order to cover substantially every square inch of horizontal cross sectional area and thereby eliminate the problem of dead zones which occur between the auger paths or non-reciprocating stirring apparatuses. A common feature of the prior art reciprocating stirring apparatuses is that the multiples of augers move back and forth in unison with each other, either because they are propelled by the same drive or because they depend from a single carriage. As a consequence of this unified motion, the coverage of substantially all horizontal cross sectional area without overlap requires that the augers be evenly spaced along the beam. This even spacing results in uneven stirring, and hence drying, due to the fact that the further each auger is located from the center point the more grain it must stir per revolution of the auger support beam.
Over stirring of grain in the central area of a bin results in more serious problems than the apparent over-use of equipment and wasted energy costs. The centrally located grain is actually augered to the top so often, as compared to the other grain, that it dries at a slower rate due to the fact that drying is usually accomplished by warm air being forced upwards through the grain after exiting from a perforated floor. In addition, the more frequent stirring results in heaping towards the bin center and consequent air flow routes which bend outwardly away from the vertical. The cumulative effect is early drying of the perimeter grain, and eventually over-drying thereof, in order to adequately dry the center portion. This phenomena occurs even though the outer portion was subject to less stirring.